DISCOURSE

ON THE

PHILOSOPHY OF ANALOGY.

Συμπαθη είναι τα ανω τοις κατω.

GENTLEMEN OF THE SOCIETY,

It was not without unfeigned reluctance, that I complied with the request to appear before you on the present occasion. Do not, however, suppose that I for a moment distrusted either your candor or your forbearance. Full well was I assured, that you would look with indulgence upon the humblest attempt to advance the science or to adorn the literature of our country. My reluctance proceeded from a different source. Accustomed to the investigation of abstract truth, I feared lest the train of my reflections should seem too far removed from the ordinary walks of literary life. I however remembered that general truth is, in its nature, abstracted, and no where could I expect that such truth would meet with more devoted

admirers than in a Society, whose only object is the cultivation of letters. Besides, I have thought that, by giving to these annual discourses the tinge of our different professional pursuits, we should enlarge the field from which subjects for discussion may be selected, and secure as great a degree of variety as the occasion may demand.

Influenced by these considerations, I venture to request your attention to some remarks which I shall offer upon THE PHILOSOPHY OF ANalogy; a subject, which, so far as I have been able to discover, has not yet attracted the particular notice of any writer in our language. This neglect is at least somewhat remarkable, for I know of none which stands more intimately connected, both with the improvement of science, and the progress of discovery. May we not, then, hope that by exploring a field, which has been so long overlooked, we may find something to reward our search, which has thus far escaped the notice of more able inquirers.

The most obvious thought that meets us, when we reflect upon the intellectual relation which man sustains to the universe around him, is, that he commences his existence entirely destitute of knowledge. He is, however, so constituted, that knowledge must inevitably result from the elements of which his intellectual character is composed, and from the circumstances under which those elements are placed. Thus, we find him endowed with a universal appetite for knowledge, which, by a law of his nature, grows by what it feeds on. Again, we find man surrounded by a universe, in all respects corresponding to this mental appetite,

and adapted, at the same moment, both to gratify and to stimulate inquiry. Knowledge, however, is acquired, neither by this appetite, nor by its relation to this universe. Man is, therefore, endowed also with. faculties, by the exercise of which he is able to discover that truth by which his desires are gratified and his intellectual happiness created.

If we consider the subject somewhat more attentively, we not only perceive that the universe is spread around us to stimulate our love of truth, but we may also discover the mode in which the successive developments of truth are addressed to the ever-growing faculties of an immortal spirit. It may not be unprofitable to occupy a few moments in illustrating this position.

The first step in the progress of knowledge is, the observation of facts, that is, that certain things exist, and that certain changes are taking place in them. This information we derive at first entirely from the

senses.

But, it is found that these changes, or, as they are technically called, phenomena, do not take place at random, but in the order of a succession, at first dimly, but, by close inspection, more clearly, seen. The order of this succession is next noted, and this forms the first conception of a law of nature. Subsequent observation and more accurate experiments determine more of the circumstances actually connected with this law of succession, disengage from it that which is accidental, extend its dominion to other changes placed by the Author of nature under its control, and thus a nearer and nearer approximation is made to pure and

unchangeable truth. Thus, in mechanics, we learn, first, the fact that bodies, under certain circumstances, without any impulse change their place. Pursuing our investigations further, we learn under what circumstances and in what direction alone this motion or change of place occurs; we ascertain the various facts or laws which pertain to the motion itself, and extend, as far as we are able, our knowledge of the objects to which these laws apply. Thus also, by knowing the laws which govern any particular class of objects, we preclude the necessity of innumerable experiments, and are enabled to predict, under given circumstances, what, throughout the material universe, will be the certain result.

Again, between the laws which govern different classes of objects, there are found to exist various points of coincidence. These points of coincidence, and the circumstances under which they occur, are also objects of knowledge. They form laws of a higher class, or more general laws, by which the less general laws themselves are governed. Thus, I mentioned that the law by which the attraction of gravity operates, is discovered. The laws by which the attraction of magnetism, and that of electricity operate, have also been discovered, and these laws are found to coincide, and hence we derive a general law of attraction, applying to gravity, magnetism, electricity, and probably to all kinds of attraction throughout the universe.

But it is evident that the progress of human knowledge is not here arrested. These general laws may be subject to others yet more general. Again, correspondences may be discovered between these and others

yet more general. Thus, at every step of our progress, we are enabled to predict not only an infinity of changes, but also an infinity of laws by which those changes are governed. Thus, I have spoken of the general law of attraction governing the laws of gravitation, electricity, and magnetism. This law of attraction may yet be found subject to some more general law, which governs both attraction and repulsion, and every species of motion. Again, these more general laws of motion may be connected with those of light, and a multitude of other classes of laws not yet discovered. And so on to infinity.

But it is still to be observed that not only is human knowledge thus continually extending, it is moreover evident that a tendency to universal extension has been impressed upon it by its Creator. For we find that a law, when legitimately established, is never known to vary. Some unexplained deviation is, however, frequently discovered in the mode of its operation. This, by the constitution of the human mind, leads to more extensive investigation. Investigation shows that the language of nature had been misinterpreted, and that every discrepancy vanishes, by adopting a wider generalization and admitting a more universal philosophical principle. Thus, to refer to the case of gravity, it was at first found that some bodies rose instead of falling in the air, and hence there seemed an exception to the law which before appeared established. More accurate experiment, however, proved that the air itself gravitated to the earth, and thus not only the exception was explained, but a wider universality was given to the general law than had been before conceded